Sampling procedures allow a more precisely knowledge of the parameter of interest and can define better the plant communities and its potential for wood production and guidelines for conservation or environmental preservation, whether in native or planted forests.  Considering different types of sample units, it’s necessary to know whether the choice of a unit can influence on quantitative parameters to be analyzed. The objective of this work was to evaluate the influence of three different types of sample units such as circular, rectangular and Bitterlich points analyzing quantitative attributes such as density, basal area, mean diameter and mean squared diameter.  These analyzes were carried out in three tropical phytophysiognomies, dense ombrophylous forest, semidecidual forest and cerradão. In general, the Bitterlich method differed from circular and rectangular units when analyzing structures of size and diversity.  Phytophysiognomy also influenced the analyzes due to the structure of differentiated size and aggregate patterns of the species. Therefore, caution is required when choosing a sample unit, because depending on the physiognomy the quantitative attributes can show different behaviors and responses.

07 - Influence of sample unit types on quantitative attributes analysis in tropical forests